Glutamatergic, GABAergic, and endocannabinoid neurotransmissions within the dorsal hippocampus modulate the cardiac baroreflex function in rats

Author(s)

Ferreira-Junior, Nilson Carlos ^[1] ; Lagatta, Davi Campos ^[1] ; Moraes Resstel, Leonardo Barbosa ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Pharmacol, 3900 Bandeirantes Ave, BR-14049900 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY; v. 470, n. 2, p. 395-411, FEB 2018.
• Web of Science Citations: 3

Abstract

The dorsal hippocampus (DH) is involved in the modulation of the cardiac baroreflex function. There is a wide expression of the NMDA and AMPA/Kainate receptors within the DH. Glutamate administration into the DH triggers both tachycardia and pressor responses. Moreover, GABAergic interneurons and endocannabinoid system play an important role in modulation of the activity of glutamatergic neurons within the DH. Therefore, the present work aimed to evaluate the involvement of the glutamatergic, GABAergic, and endocannabinoid neurotransmissions within the DH in cardiac baroreflex function in rats. We have used the technique of vasoactive drugs infusion to build both sigmoidal curves and linear regressions to analyze the cardiac baroreflex function. Bilateral injection into the DH of DL-AP7, a NMDA receptor antagonist (10 or 50 nmol/500 nL), or NBQX, an AMPA/Kainate antagonist (100 nmol/ 500 nL), reduced the cardiac baroreflex function. On the other hand, bilateral injection of Bicuculline, a GABA(A) receptor antagonist (1 nmol/500 nL), or AM251, a CB1 receptor antagonist (10 or 100 pmol/500 nL), increased the cardiac baroreflex function. Furthermore, 1 nmol/500 nL of the NMDA receptor antagonist, when administrated alone, was ineffective to change baroreflex function, but it was able to inhibit the alteration in the cardiac baroreflex function elicited by the dose of 100 pmol/500 nL of the CB1 receptor antagonist. Taken together, these findings suggest that glutamatergic, GABAergic, and endocannabinoid neurotransmissions interact each other within the DH to modulate the cardiac baroreflex function. (AU)

• FAPESP's process: 11/19494-8 - Involvement of the dorsal hippocampus in the modulation of cardiac baroreflex activity: implication of NMDA, CB1, TRPV1 and muscarinic receptors and of the nitric oxide.
• Grantee: Nilson Carlos Ferreira Junior
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/07332-3 - Possible role of dorsal hippocampus on behaviour and autonomic responses during defensive responses: involvement of NMDA receptor/nitric oxide and endocanabinoid
• Grantee: Leonardo Resstel Barbosa Moraes
• Support Opportunities: Regular Research Grants